26.3.2 Traveling Salesman Problem

The TSP (Traveling Salesman Problem) is the classic combinatorial
optimization problem. I have provided a very simple version of it,
based on the coordinates of twelve cities in the southwestern United
States. This should maybe be called the Flying Salesman Problem,
since I am using the great-circle distance between cities, rather than
the driving distance. Also: I assume the earth is a sphere, so I don’t
use geoid distances.

The gsl_siman_solve routine finds a route which is 3490.62
Kilometers long; this is confirmed by an exhaustive search of all
possible routes with the same initial city.

The full code can be found in siman/siman_tsp.c, but I include
here some plots generated in the following way: